Recent studies in the laboratory have linked mutations in the p53 gene with development of many types of malignancies. The availability of a genetic marker for cancer predisposition raises many important questions for which p53 acts as a paradigm. The specific research aims are: 1. To determine the demand for carrier testing among families of pediatric cancer patients, using p53 as a paradigm. 2. To develop a protocol for pre-test evaluation and education in this population. 3. To assess our curriculum for cancer prevention education in survivors of childhood cancer, and study the importance of risk assessment in efficacy of cancer prevention education. 4. To screen 170 individuals with a history of sarcoma for constitutional p53 mutations and determine the prevalence of mutations among the subtypes of childhood sarcoma; to study family histories of these patients and to study the natural history of their diseases. As a recipient of a Preventive Oncology Academic Award, I will also pursue training in cancer prevention, including formal coursework in epidemiology, biostatistics and cancer control.